Research on Precise Point Positioning Method of BDS-2/BDS-3 Mixed-Frequency Based on Low-Cost u-blox

摘要

Precise Point Positioning (PPP) is the best navigation method for low-cost receivers in applications such as smart transportation and mobile phones. With the global networking of the Beidou Satellite Navigation System (BDS), although BDS-2/BDS-3 can provide sufficient observable satellite data, the low-cost dual-frequency receiver has the problem of limited dual-frequency observation and satellite collection. The difference of BDS-2/BDS-3 signal frequency band inevitably introduce new Inter-Frequency Bias (IFB). These lead to reduced PPP positioning performance. Therefore, this paper proposes a BDS-2/BDS-3 mixed-frequency undifferenced and uncombined PPP (MF-PPP) method based on low-cost u-blox. On the one hand, when BDS-2 dual-frequency undifferenced and uncombined PPP (DF-PPP) is used, the Position Dilution Of Precision (PDOP) is reduced by adding single-frequency BDS-2/BDS-3 satellites. On the other hand, through the BDS satellite-side uncali-brated code delay (UCD) combined modeling method completes the IFB reg-ularization. These construct the MF-PPP model. The final test results show that, compared with BDS-2 dual-frequency, BDS-2/BDS-3 MF-PPP effectively reduces the PDOP value, thereby improving the positioning accuracy. The overall accuracy of the BDS system is increased by 46.9%, and the convergence time is reduced by 27.1%. Therefore, compared to the traditional dual-frequency PPP method, the MF-PPP method is more suitable for the low-cost and high-precision mass market.